This invention relates to air cushion supported vehicles, and more particularly to marine vessels such as are referred to as surface effect ships ("SES"). Specifically, the invention relates to improvements in flexible air cushion seal systems such as for the stern ends of such vessels of the type which comprise one or more inflatable "lobes" provided to extend between the sidehulls or skegs of the ship as shown for example in U.S. Pat. Nos. 3,977,491; 4,090,459, and now pending co-assigned U.S. patent application Ser. No. 434,590, filed Oct. 15, 1982. Also, such seal systems may be employed as partitioning keels or skegs in such craft for improved operational stability purposes; such as is shown for example at 28 in U.S. Pat. No. 3,524,517.
Such seal devices are hingedly affixed to the hull structure so as to bridge the water/air cushion space beneath the ship, while being adapted to vertically float between the sidehulls of the ship in conformity with operational variances in the height of the air cushion under the ship so as to maintain the air cushion support under the vessel. As such seal systems flex vertically, the opposite ends of the lobes slide and rub against the adjacent stationary structures of the vehicle; and due to sidehull plating irregularities, variable sidehull geometries, and sea state encountered side loads thereon during operation of the vessel, such rubbing action between the sidehulls and the seal lobe components has heretofore resulted in early loss of efficient performance and serious maintenance cost problems.
In surface effect ships having air cushion seals of this type, it is the lowermost air cushion sealing lobe of the system that is most subject to a large variety of wave-buffeting/distortioning and frictional wearing stresses; and it is the purpose of this invention to provide for such a seal system an improved lower lobe construction which substantially reduces installation and maintenance expenses relative to the frictional wear effects on the lobe parts. The invention also minimizes water scooping problems while at the same time providing an operationally stabilized lobe construction which in consequence provides an improved overall air cushion sealing capability.